1. Field
Example embodiments relate to power sources, and/or more particularly, to high electron mobility transistors and methods of manufacturing the same.
2. Description of the Related Art
In a power conversion system, an efficiency of the entire system may depend upon an efficiency of a power switching device. As a switching device, a power metal oxide semiconductor field effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT) using silicon has been mainly used. However, increasing an efficiency of a switching device may be limited due to material limitations of silicon.
To overcome the limitation of the silicon material, research into a high electron mobility transistor (HEMT) is being actively conducted.
A HEMT may include semiconductor layers having different electrical polarization characteristics. A semiconductor layer having a relatively large polarizability in the HEMT may cause a two-dimensional electron gas (2DEG) in other semiconductor layers that are hetero-bonded with the semiconductor layer. The 2DEG may be used as a channel between a drain electrode and a source electrode, and an electric current flowing in the channel may be controlled according to a bias voltage applied to a gate electrode.
Meanwhile, the HEMT may include a fast recovery diode (FRD) for freewheeling current of the HEMT and stabilizing a voltage change rate in order to limit an avalanche breakdown. An avalanche breakdown may occur when a HEMT is turned off. A FRD may be connected to the HEMT in parallel.
However, as described above, if the FRD is connected to the HEMT as an additional device, an additional process for fabricating the FRD may be necessary, and accordingly, a size of the HEMT may increase, and fabrication costs also may increase.